1 /*
2  * Defines interfaces for interacting wtih the Raspberry Pi firmware's
3  * property channel.
4  *
5  * Copyright © 2015 Broadcom
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/dma-mapping.h>
13 #include <linux/mailbox_client.h>
14 #include <linux/module.h>
15 #include <linux/of_platform.h>
16 #include <linux/platform_device.h>
17 #include <soc/bcm2835/raspberrypi-firmware.h>
18 
19 #define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
20 #define MBOX_CHAN(msg)			((msg) & 0xf)
21 #define MBOX_DATA28(msg)		((msg) & ~0xf)
22 #define MBOX_CHAN_PROPERTY		8
23 
24 struct rpi_firmware {
25 	struct mbox_client cl;
26 	struct mbox_chan *chan; /* The property channel. */
27 	struct completion c;
28 	u32 enabled;
29 };
30 
31 static DEFINE_MUTEX(transaction_lock);
32 
33 static void response_callback(struct mbox_client *cl, void *msg)
34 {
35 	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
36 	complete(&fw->c);
37 }
38 
39 /*
40  * Sends a request to the firmware through the BCM2835 mailbox driver,
41  * and synchronously waits for the reply.
42  */
43 static int
44 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
45 {
46 	u32 message = MBOX_MSG(chan, data);
47 	int ret;
48 
49 	WARN_ON(data & 0xf);
50 
51 	mutex_lock(&transaction_lock);
52 	reinit_completion(&fw->c);
53 	ret = mbox_send_message(fw->chan, &message);
54 	if (ret >= 0) {
55 		wait_for_completion(&fw->c);
56 		ret = 0;
57 	} else {
58 		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
59 	}
60 	mutex_unlock(&transaction_lock);
61 
62 	return ret;
63 }
64 
65 /**
66  * rpi_firmware_property_list - Submit firmware property list
67  * @fw:		Pointer to firmware structure from rpi_firmware_get().
68  * @data:	Buffer holding tags.
69  * @tag_size:	Size of tags buffer.
70  *
71  * Submits a set of concatenated tags to the VPU firmware through the
72  * mailbox property interface.
73  *
74  * The buffer header and the ending tag are added by this function and
75  * don't need to be supplied, just the actual tags for your operation.
76  * See struct rpi_firmware_property_tag_header for the per-tag
77  * structure.
78  */
79 int rpi_firmware_property_list(struct rpi_firmware *fw,
80 			       void *data, size_t tag_size)
81 {
82 	size_t size = tag_size + 12;
83 	u32 *buf;
84 	dma_addr_t bus_addr;
85 	int ret;
86 
87 	/* Packets are processed a dword at a time. */
88 	if (size & 3)
89 		return -EINVAL;
90 
91 	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
92 				 GFP_ATOMIC);
93 	if (!buf)
94 		return -ENOMEM;
95 
96 	/* The firmware will error out without parsing in this case. */
97 	WARN_ON(size >= 1024 * 1024);
98 
99 	buf[0] = size;
100 	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
101 	memcpy(&buf[2], data, tag_size);
102 	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
103 	wmb();
104 
105 	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
106 
107 	rmb();
108 	memcpy(data, &buf[2], tag_size);
109 	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
110 		/*
111 		 * The tag name here might not be the one causing the
112 		 * error, if there were multiple tags in the request.
113 		 * But single-tag is the most common, so go with it.
114 		 */
115 		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
116 			buf[2], buf[1]);
117 		ret = -EINVAL;
118 	}
119 
120 	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
121 
122 	return ret;
123 }
124 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
125 
126 /**
127  * rpi_firmware_property - Submit single firmware property
128  * @fw:		Pointer to firmware structure from rpi_firmware_get().
129  * @tag:	One of enum_mbox_property_tag.
130  * @tag_data:	Tag data buffer.
131  * @buf_size:	Buffer size.
132  *
133  * Submits a single tag to the VPU firmware through the mailbox
134  * property interface.
135  *
136  * This is a convenience wrapper around
137  * rpi_firmware_property_list() to avoid some of the
138  * boilerplate in property calls.
139  */
140 int rpi_firmware_property(struct rpi_firmware *fw,
141 			  u32 tag, void *tag_data, size_t buf_size)
142 {
143 	/* Single tags are very small (generally 8 bytes), so the
144 	 * stack should be safe.
145 	 */
146 	u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
147 	struct rpi_firmware_property_tag_header *header =
148 		(struct rpi_firmware_property_tag_header *)data;
149 	int ret;
150 
151 	header->tag = tag;
152 	header->buf_size = buf_size;
153 	header->req_resp_size = 0;
154 	memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
155 	       tag_data, buf_size);
156 
157 	ret = rpi_firmware_property_list(fw, &data, sizeof(data));
158 	memcpy(tag_data,
159 	       data + sizeof(struct rpi_firmware_property_tag_header),
160 	       buf_size);
161 
162 	return ret;
163 }
164 EXPORT_SYMBOL_GPL(rpi_firmware_property);
165 
166 static void
167 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
168 {
169 	u32 packet;
170 	int ret = rpi_firmware_property(fw,
171 					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
172 					&packet, sizeof(packet));
173 
174 	if (ret == 0) {
175 		struct tm tm;
176 
177 		time_to_tm(packet, 0, &tm);
178 
179 		dev_info(fw->cl.dev,
180 			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
181 			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
182 			 tm.tm_hour, tm.tm_min);
183 	}
184 }
185 
186 static int rpi_firmware_probe(struct platform_device *pdev)
187 {
188 	struct device *dev = &pdev->dev;
189 	struct rpi_firmware *fw;
190 
191 	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
192 	if (!fw)
193 		return -ENOMEM;
194 
195 	fw->cl.dev = dev;
196 	fw->cl.rx_callback = response_callback;
197 	fw->cl.tx_block = true;
198 
199 	fw->chan = mbox_request_channel(&fw->cl, 0);
200 	if (IS_ERR(fw->chan)) {
201 		int ret = PTR_ERR(fw->chan);
202 		if (ret != -EPROBE_DEFER)
203 			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
204 		return ret;
205 	}
206 
207 	init_completion(&fw->c);
208 
209 	platform_set_drvdata(pdev, fw);
210 
211 	rpi_firmware_print_firmware_revision(fw);
212 
213 	return 0;
214 }
215 
216 static int rpi_firmware_remove(struct platform_device *pdev)
217 {
218 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
219 
220 	mbox_free_channel(fw->chan);
221 
222 	return 0;
223 }
224 
225 /**
226  * rpi_firmware_get - Get pointer to rpi_firmware structure.
227  * @firmware_node:    Pointer to the firmware Device Tree node.
228  *
229  * Returns NULL is the firmware device is not ready.
230  */
231 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
232 {
233 	struct platform_device *pdev = of_find_device_by_node(firmware_node);
234 
235 	if (!pdev)
236 		return NULL;
237 
238 	return platform_get_drvdata(pdev);
239 }
240 EXPORT_SYMBOL_GPL(rpi_firmware_get);
241 
242 static const struct of_device_id rpi_firmware_of_match[] = {
243 	{ .compatible = "raspberrypi,bcm2835-firmware", },
244 	{},
245 };
246 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
247 
248 static struct platform_driver rpi_firmware_driver = {
249 	.driver = {
250 		.name = "raspberrypi-firmware",
251 		.of_match_table = rpi_firmware_of_match,
252 	},
253 	.probe		= rpi_firmware_probe,
254 	.remove		= rpi_firmware_remove,
255 };
256 module_platform_driver(rpi_firmware_driver);
257 
258 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
259 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
260 MODULE_LICENSE("GPL v2");
261